Wireless telephones are well known in the art. In general, such telephones are mobile stations such that a user may use the telephone for communication anywhere within a particular geographic serving area. Continuous communication is provided even as the telephone moves about within the serving area. Such continuous service is provided in wireless cellular networks by providing radio base stations (RBS) throughout the geographic serving area. Each base station provides service to a geographic area, called a cell. As a mobile station moves from one cell to another, continuous service is provided by "handing off" the mobile station from one cell to another. In order to provide service to a large number of users, sophisticated frequency sharing plans must be used. The architecture and operation of such cellular wireless systems are well known in the art and will not be described in detail herein.
More recently, the notion of fixed wireless access has become of interest in the area of wireless communications. In a fixed wireless access system, wireless stations (e.g. wireless telephones), are provided with service from a wireless network. However, the wireless stations are expected to be fixed in a prescribed geographic location (e.g., a subscriber's home). In a fixed wireless system, service can be provided to more subscribers with less system resources because no system resources need to be spent on mobility tracking and handoff procedures. Further, since the location of fixed wireless stations are known, the available frequency spectrum can be used more efficiently because interference between users can be better managed.
Thus, service may be provided to fixed wireless subscribers at a lower cost as compared to the equivalent mobile wireless subscriber. A problem arises in that a given wireless telephone may be able to obtain service from a service provider in both a mobile wireless capacity and a fixed wireless capacity. From the service provider point of view, this is a problem because the service provider wants to differentiate fixed wireless service from mobile wireless service. This differentiation may be made on the basis of cost or the types of services provided. Thus, a fixed wireless subscriber should be limited to using the wireless system at the subscriber's fixed location. Alternatively, the fixed wireless subscriber should have to pay a higher rate when using the wireless telephone as a mobile telephone outside of the subscriber's fixed location.
In order for a service provider to handle these situations, the location of the wireless station must be known. There are several existing techniques for determining the location of a mobile station. For example, in several known techniques, the location of a mobile station can be determined by first computing the mobile stations distance from at least three base stations, and then using triangulation to compute the geographic location of the mobile station. For example, U.S. Pat. No. 5,646,632 discloses a technique for use in a code division multiple access (CDMA) system in which a mobile station can identify its own location using time delays of pilot signals received from nearby base stations.